Magnetoresistive effect element, magnetic memory device and method of fabricating the same

Abstract

A magnetoresistive effect element includes a laminated body including a magnetosensitive layer a magnetizing direction of which is changed by an external magnetic field and constituted such that a current is made to flow in a direction orthogonal to a laminated layer face thereof, and a annular magnetic layer arranged at a side of one face of the laminated body to constitute an axial direction by a direction along the laminated layer face and constituted to be penetrated by a plurality of lead wires and therefore, a closed magnetic path can be formed by making current flow to a plurality of lead wires and inversion of magnetization at the magnetosensitive layer can further efficiently be carried out.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a magnetoresistive effect element including a ferromagnetic substance a magnetizing direction of which is changed by an external magnetic field, a magnetic memory device for storing information by utilizing a change in the magnetizing direction, and a method of fabricating the same.[0002]Conventionally, as a general-purpose memory used in information processing apparatus of a computer, a communication apparatus and the like, a volatile memory such as DRAM, SRAM or the like is used. The volatile memories need to refresh by incessantly supplying current for holding memory. Further, since all the information is lost when a power source is cut off, a nonvolatile memory needs to install as means for recording information other than the volatile memories and, for example, flash EEPROM, a magnetic hard disk device or the like is used therefor.[0003]In the nonvolatile memories, high speed access poses an important problem in ...

AI Technical Summary

Benefits of technology

[0011]The invention has been carried out in view of such a problem and it is a first object of the invention to provide a magnetic memory device capable of carrying out stable writing operation by efficiently utilizing a stronger magnetic field and a magnetoresistive effective element mounted thereon. It is a second object thereof to provide a magnetic memory device less effecting adverse influence on a contiguous memory cell and a magnetoresistive effective element mounted thereon. Further, it is a third object thereof to provide a method of easily fabricating such a magnetic memory device.

Problems solved by technology

Further, since all the information is lost when a power source is cut off, a nonvolatile memory needs to install as means for recording information other than the volatile memories and, for example, flash EEPROM, a magnetic hard disk device or the like is used therefor.

In the nonvolatile memories, high speed access poses an important problem in accordance with tendency of high speed information processing.

However, this value is insufficient for achieving a further increase in the storing speed or a further increase in the access speed.

However, even in the case of MRAM utilizing the TMR element showing the resistance change rate of about 40%, output voltage is about several tens mV and therefore, the output voltage is insufficient for realizing a magnetic memory device having a higher density.

Further, in the case of MRAM utilizing the TMR effect, information is stored to each memory cell by changing a magnetizing direction of a magnetic film by an induced magnetic field by current flowing in lead wires which are arranged orthogonal to each other, that is, a current magnetic field, however, the current magnetic field is an open (not confined to a specific region magnetically) magnetic field and therefore, not only the efficiency is low but also there is a concern of effecting adverse influence on a contiguous memory cell.

Further, in the case of achieving higher density formation of a magnetic memory device by highly integrating memory cells, miniaturization of a TMR element is indispensable, however, there is a concern of the following problem.

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